#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>

typedef long long ll;

const ll mod=1e9+7;

const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};

#define all(x) x.begin(),x.end()
#define allr(x) x.rbegin(),x.rend()
#define rc(x)  return cout<<x<<"\n",0
#define sz(s)  (int) s.size()
#define pb push_back
#define mp make_pair
#define fr first
#define sc second
#define PI 3.14159265358979

using namespace std;

ll t,n,a,b,k;

int main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	ifstream cin("divk.in");
	ofstream cout("divk.out");
	cin >> n >> k >> a >> b;
	ll v[n+2]={0},f[n+2]={0};
	ll ans=0;
	for (int i=1; i<=n; i++) {
		ll x;
		cin >> x;
		v[i]=(v[i-1]+x)%k;
		if (i-b>0) {
			f[v[i-b-1]]--;
		}
		if (i-a>=0) {
			f[v[i-a]]++;
		}
		ans+=f[v[i]];
	}
	cout << ans << '\n';
}